Set Channel’s alpha with masks does not work if set to same layer
The Set Channel effect does not seem to respect masks for the alpha source anymore, if the layer refers to itself.
When „Source Layer 4“ points to the same layer it is applied to, with the dropdown set to „Masks“, the effect would apply the layer’s alpha, but only within the layer’s masks. Now, it does not respect the masks at all and won’t apply the alpha.
Simple Setup: red shape layer with a mask, „Solid Composite“ with green color applied, then „Set Channels“ with „Source Layer 4“ set to the same shape layer, using „Masks“. See attached images for what the setup did before and what it is doing now.
The effect still seems to be working fine, as long as the alpha refers to another layer.
The issue might be related to the recent revision of the Set Channel effect with the may 2020 update: https://helpx.adobe.com/after-effects/using/whats-new/2020-1.html#Otherenhancements
Thank you for reporting this issue, we are able to reproduce it on our end as well. Thank you for the reference to the update to Set Channels as well, that is very helpful. We are now tracking this issue internally as DVAAE-4215869 and this thread will be kept updated.
Thanks again and apologies for any inconvenience this change has caused,
- John, After Effects Engineering Team